Stereoselective preparations of epoxy-, fluoro- and related derivatives of ricinoleic acid and 13(S)-hydroxyoctadeca-9(Z),11(E)-dienoic acid

• Main Authors: Omar, Muhammad Nor, Hamilton, Richard J, Moynihan, Humphrey A
• Format: Article
• Language: English
• Published: ARKAT USA Inc 2003
• Subjects: QD Chemistry
• Online Access: http://irep.iium.edu.my/24437/1/Stereoselective_preparation_of_related_derivatives_of_ricinoleic_and_13S_HODE.pdf; http://irep.iium.edu.my/24437/; http://www.arkat-usa.org/about-arkat-usa/
• Institution: Universiti Islam Antarabangsa Malaysia

Methyl ricinoleate 4 and methyl 13(S)-hydroxyoctadeca-9(Z),11(E)-dienoate 7 were subjected to epoxidation using mCPBA, or tert-butyl hydroperoxide in the presence of vanadyl acetylacetonate or titanium (IV) isopropoxide with D-(-)- or L-(+)-diisopropyl tartrate. Epoxidations using mCPBA gave equal quantities of the disatereoisomeric epoxides 5/6 and 8/9 from 4 and 7 respectively. Other methods gave preferentially epoxides 5 or 8, except for treatment of 7 with tert-butyl hydroperoxide in the presence of titanium (IV) isopropoxide and L-(+)-diisopropyl tartrate which gave preferentially epoxide 9. Hydroxy-derivative 4, 7, 5, 6, 8 and 9 were converted into the fluoro-derivatives 16 - 21 by trimethylsilylation and treament with diethylaminosulphur trifluoride. Epoxides 6 and 9 were converted into 2-oxazolines 22 and 23 respectively by reaction with acetamide.